<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>

        console.log(Boolean('hello world')); // true

        var num = 1;

        console.log(Boolean(num)); // true
        console.log(!!num); // true

    </script>
</body>
</html>